Submission #1156898

#TimeUsernameProblemLanguageResultExecution timeMemory
1156898Zero_OPTriple Jump (JOI19_jumps)C++20
100 / 100
714 ms119984 KiB
#include <bits/stdc++.h>

using namespace std;

//loops (warning : long long)
#define FOR(i, l, r) for(int i = (l); i < (r); ++i)
#define ROF(i, r, l) for(int i = (r - 1); i >= l; --i)

//pairs, tuples
#define mp make_pair
#define mt make_tuple
#define ff first
#define ss second

//vectors
#define all(v) begin(v), end(v)
#define rall(v) rbegin(v), rend(v)
#define pb push_back
#define eb emplace_back
#define sum_of(v) accumulate(all(v), 0ll)
#define sz(v) (int)v.size()
#define compact(v) v.erase(unique(all(v)), end(v))

//binary search
#define lwb lower_bound
#define upb upper_bound

//other stuffs
#define dbg(x) "[" #x " = " << (x) << "]"
#define file(task) if(fopen(task".inp", "r")){ freopen(task".inp", "r", stdin); freopen(task".out", "w", stdout); }

template<typename T>
bool minimize(T& a, const T& b){
    if(a > b) return a = b, true;
    return false;
}

template<typename T>
bool maximize(T& a, const T& b){
    if(a < b) return a = b, true;
    return false;
}

using ll = long long;
using ull = unsigned long long;
using ld = long double;
using db = double;
using pi = pair<int, int>;
using pl = pair<ll, ll>;

using vi = vector<int>;
using vb = vector<bool>;
using vl = vector<ll>;
using vpi = vector<pi>;
using vpl = vector<pl>;

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

const int MAX = 5e5 + 5;
const ll inf = 1e15;

int N, Q, pre[MAX];
ll A[MAX], result[MAX];
vpi queries[MAX];
vpi events[MAX];

struct Node{
    ll result, max_f, max_v;
    Node() : result(0), max_f(-inf), max_v(-inf) {}
    
    friend Node operator + (const Node& a, const Node& b){
        Node c;
        c.result = max({a.result, b.result, a.max_f + b.max_v});
        c.max_f = max(a.max_f, b.max_f);
        c.max_v = max(a.max_v, b.max_v);
        return c;
    }

    void debug(){
        cout << dbg(result) << dbg(max_f) << dbg(max_v);
    }
};

struct SegmentTree{
    vector<Node> st;
    SegmentTree(int n) : st(n << 2) {}

    void update_f(int id, int l, int r, int pos, ll v){
        // if(id == 1){
        //     cout << "update_f : " << pos << ' ' << v << '\n';
        // }

        if(l == r) maximize(st[id].max_f, v);
        else{
            int mid = l + r >> 1;
            if(pos <= mid) update_f(id << 1, l, mid, pos, v);
            else update_f(id << 1 | 1, mid + 1, r, pos, v);
            st[id] = st[id << 1] + st[id << 1 | 1];
            // cout << st[id].result << '\n';
        }
    }

    void update_v(int id, int l, int r, int pos, ll v){
        // if(id == 1){
        //     cout << "update_v : " << pos << ' ' << v << '\n';
        // }

        if(l == r) maximize(st[id].max_v, v);
        else{
            int mid = l + r >> 1;
            if(pos <= mid) update_v(id << 1, l, mid, pos, v);
            else update_v(id << 1 | 1, mid + 1, r, pos, v);
            st[id] = st[id << 1] + st[id << 1 | 1];
            // cout << st[id].result << '\n';
        }
    }

    Node query(int id, int l, int r, int u, int v){
        if(v < l || u > r) return Node();
        if(u <= l && r <= v) {
            // cout << dbg(l) << dbg(r) << ' '; st[id].debug(); cout << '\n';
            return st[id];
        }
        int mid = l + r >> 1;
        return query(id << 1, l, mid, u, v) + query(id << 1 | 1, mid + 1, r, u, v);
    }
};

void add(int i, int j){
    if(2*j - i < N){
        // cout << i << ' ' << j << ' ' << A[i] + A[j] << ' ' << 2 * j - i << '\n';
        events[i].eb(A[i] + A[j], 2*j - i - 1);
    }
}

void testcase(int ntestcase){
    cin >> N;
    FOR(i, 0, N){
        cin >> A[i];
    }

    stack<int> st;
    FOR(i, 0, N){
        while(!st.empty() && A[st.top()] <= A[i]) {
            add(st.top(), i);
            st.pop();
        }
        pre[i] = (st.empty() ? -1 : st.top());
        if(pre[i] != -1) add(pre[i], i);
        st.push(i);
    } 

    //Only O(N) (i, j, ?)

    cin >> Q;
    FOR(i, 0, Q){
        int l, r;
        cin >> l >> r;
        --l, --r;
        queries[l].eb(r, i);
    }

    SegmentTree T(N);
    ROF(i, N, 0){
        // cout << dbg(i) << '\n';
        T.update_v(1, 0, N-1, i, A[i]);
        for(auto [earn, pos] : events[i]){
            T.update_f(1, 0, N-1, pos, earn);
        }

        for(auto [j, id] : queries[i]){
            // cout << "calc " << i << ' ' << j << '\n';
            result[id] = T.query(1, 0, N-1, i, j).result;
        }
    }

    FOR(i, 0, Q){
        cout << result[i] << '\n';
    }
}

int main(){
    ios_base::sync_with_stdio(0); cin.tie(0);

#ifdef LOCAL
    freopen("task.inp", "r", stdin);
    freopen("task.out", "w", stdout);
#endif // LOCAL

    int T = 1;
//    cin >> T;
    FOR(i, 0, T) testcase(i);

    return 0;
}

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